The present invention relates to a system, apparatus, and methodology involving dielectric microwave scanning, or illuminating, screening, of a human subject, and in particular to such scanning which is done for the purpose of detecting, in relation to baseline physiologic response data, and according to defined screening criteria, notable differences, or anomalies, in relation to a given individual's “dielectric signature”.
While there are many applications in which the system, apparatus and methodology of this invention find substantial practical utility, two specific such fields of activity are particularly noted herein, and one of these is employed as a principal model for discussing and explaining the structure and operation of this invention. These two areas include (a) security detection, or scanning, at locations such as airports for the purpose of detecting weapons, contraband, etc., and (b) authorized access control for personnel in sensitive areas, for example, in relation to research and development areas within a business. Many other useful applications will come to mind to those generally skilled in the art.
The present invention departs from, and offers certain improvements, over, a predecessor system and methodology which are fully illustrated and described in U.S. Pat. No. 6,057,761, issued May 2, 2000, for “Security System and Method”. These improvements, which exist in certain areas involving both mechanical and electrical aspects of the scanning process and structure per se, result in the present invention having certain preferential utility in particular applications, such as in applications involving airport-security screening areas where a very high throughput of people needs to be accommodated. In terms of how scanned data is ultimately read (monitored and evaluated) to detect dielectric anomalies that are important to detect, substantially the same technology (for that area of this subject matter) which is described in the just-mentioned '761 patent is also employed, for the most part, in the improved invention version which is disclosed in this document.
In general terms, and with specific reference to the improvement characteristics of the present invention just generally referred to, whereas in the '761 system and methodology scanning/screening takes place with a person standing inside of a substantially fully encircling enclosure defining an interrogation region, which enclosure rotates during actual microwave-illumination scanning, in other words with relative motion taking place between specific microwave scanning instrumentalities and a person, according to the present invention, there is substantially no relative motion that occurs between a subject and the scanning instrumentalities during microwave scanning activity.
Further, whereas in the '761 system the geometry there is such that persons in a line awaiting scanning generally feed from a single lineup of people, the present invention promotes a unique quadrature lineup of two lines of people, from which, alternately, people from the head of each line enter, one after another, a relatively open (not fully encircling) scanning-zone structure, and depart along an angled, quadrature path with respect to the direction in which they entered. Each scanning operation (subject scanning procedure) involves a short (in time) quadrature rotation, for repositioning purposes, of the dielectric scanning instrumentalities (or devices) which actually perform the electronic part of the scanning operation. With respect to the scanning of a single individual, one such quadrature rotation occurs between two stopped and fixed positions, wherein electronic scanning data is captured in a non-relative-motion sense (as was mentioned just above), with the scanning structure then being quadrature re-positioned, so-to-speak, to receive and accommodate the subject at the head of the other line which is oriented in quadrature relative to the line from which the last-scanned subject came. This operation will become clearly evident from a review of several herein-included drawing figures to be discussed shortly.
Additionally, whereas in the '761 approach to scanning, arrays of independent transmitter and receiver antenna units function to direct (transmit) electromagnetic microwave energy, and to receive returned energy, respectively, in the present invention transmission and reception are performed simultaneously by arrays of singular, co-axial transmitter/receiver antenna units that are arranged in rows and columns carried by tile-like structures, as will be explained shortly.
Much of the important background and operational setting for the present invention is well presented in the '761 patent disclosure, and accordingly, the readers of this document are encouraged to review the text of the '761 patent, which patent is hereby expressly incorporated herein by reference.
Also lying in the historical background of the present invention are several other issued U.S. Patents whose contents are entirely herein also incorporated by reference. These patents include: U.S. Pat. No.: 4,234,844, issued Nov. 18, 1980, for “Electromagnetic Noncontacting Measuring Apparatus”; U.S. Pat. No. 4,318,108, issued Mar. 2, 1982, for “Bidirectionally Focusing Antenna”; U.S. Pat. No. 4,878,059, issued Oct. 31, 1989, for “Farfield/Nearfield Transmission/Reception Antenna”; U.S. Pat. No. 4,947,848, issued Aug. 14, 1990, for “Dielectric-Constant Change Monitoring”; U.S. Pat. No. 4,949,094, issued Aug. 14, 1990, for “Nearfield/Farfield Antenna With Parasitic Array”; U.S. Pat. No. 4,975,968, issued Dec. 4, 1990, for “Timed Dielectrometry Surveillance Method and Apparatus”
Regarding the dielectric scanning process which is implemented by the present invention, as a general statement regarding the relevant physics, all materials have what is known as a dielectric constant which is associated with their physical, electrical (electromagnetic and electrostatic) properties. As a consequence, when exposed to different wavelengths and frequencies of microwave radiation, each material produces a reflection reaction, or response, to that radiation, which response, in nature, is uniquely related, among other things, to the particular material's respective dielectric constant. By subjecting a material to controlled, transmitted, microwave energy, it is possible to interpret a material's “response” thereto in terms of its dielectric constant. The term “dielectric signature” is employed herein to refer to this phenomenon.
Where plural, different characters of materials are closely united in a selected volume of space, microwave radiation employed to observe and detect the “dielectric signature” of that “space” will elicit a response which is based upon an averaging phenomenon in relation to the respective dielectric-constant contributions which are made in that space by the respective, different, individual material components. This averaging condition plays an important role in the effectiveness of the present invention, and this role is one which the reader will find fully described and discussed in the above-mentioned '761 patent.
With reliance on this role, and now briefly stated, the system and methodology of this invention are designed to direct microwave radiation into the human anatomy (at completely innocuous levels regarding any damage threat to tissue, body fluids, or bone) in such a fashion that it will effectively engage a volumetric space within the body wherein there are at least two, different (boundaried) anatomical materials, each characterized by a different dielectric constant, which materials co-contribute, in the above-mentioned “averaging” manner, to the “effective”, apparent “uniform” (or nominal homogeneous) dielectric constituent of the whole space. As is explained in the '761 patent, by so designing the invention to engage the mentioned at-least-two-material volumetric space inside the anatomy, the likelihood that a weapon, or an article of contraband, will, by the nature of its own dielectric constant, and/or its specific configuration and shape, and/or its precise location and/or disposition relative to the human body, will “fool” the invention by masquerading as a normal and expectable anatomical constituent, is just about nil. Preferably the “penetration depth” of this internal anatomical space is about 2½-wavelengths of the system operating frequency as measured mechanically in material having the mentioned “normal” dielectric constant.
If and when a foreign object, such as a weapon, or a contraband object, is borne by a person, for example closely against the outside the body, the presence of this object will, therefore, and does, change the average dielectric constant of the material content of the volume of space (anatomy, of course, included) which is occupied, in a very non-normal-anatomical, and detectable, manner, by the mentioned microwave radiation. Definitively, the presence of such non-expected (non-anatomical physiologic) material significantly changes the average value of the effective, average and apparent, uniform, spatial dielectric constant, in accordance with the averaging phenomena just mentioned above, and creates a situation wherein a distinctly different-than-expected dielectric signature appears as a responsive result of microwave scanning transmission in accordance with the invention.
Further describing important distinctions that exist between prior art conventional practice, and practice performed in accordance with the present invention, whereas conventional scanning systems are designed to look for and identify a rather large number of specific objects and materials, the approach taken according to the present invention is based upon examining human physiology for physiologic irregularities/abnormalities which are not expected to be part of the usual human, physiologic, dielectric signature (within a range of course) that essentially all people's bodies are expected to produce. As a consequence of this quite different approach for scanning, the system and methodology of this invention are significantly more efficient, and quicker, in terms of identifying weaponry, contraband, etc. problem situations. Any out-of-norm physiologic signature which is detected produces an alarm state, which state can be employed to signal the need to security people to take a closer look at what the particular, just-scanned subject involved might have on his or her person.
According to a preferred embodiment and manner of practicing the invention, a kiosk-like unit is provided into which a party to be scanned steps through an open, subject entry-way which is defined by a pair of spaced opposing upright panels, each of which carries an array of combined, coaxial microwave transmitters and receivers. These two panels effectively define an always open and exposed through-passage through the region between them, which region is referred to herein as a scanning zone, or chamber. These panels also define what is referred to herein as a panel-orientation-determined path for the passage of a person through the scanning zone. A complete scan of a human subject takes place in two stages, with, in one stage, these panels being located on one set of opposite sides of the body, such as on the left and right sides of a person, and in the other stage, the panels being disposed in a quadrature-related condition (having been rotated ninety-degrees) to perform a second scan which is taken along the two orthogonally related body sides, such as the front and rear sides of the person. Between these two scan orientations, the panels are rotated (as was just noted) through a ninety-degree arc, and in each of the two scanning positions, there is essentially no relative motion which takes place between the panels and the subject standing between them.
A unique processing feature of the present invention, with respect to the handling and scanning of large numbers of people such as must be handled at airport security locations, is that the system of the invention allows for the creation, essentially, of two, generally orthogonally related lines of people waiting to be scanned, with successive people who are scanned entering the scanning zone, one after another, and alternately, from the heads of each of the two orthogonally related lines. A person to be scanned initially faces the scanning zone with a clear (see-through) view into (and through) that zone between the two panels. That person steps into the zone between the two panels, whereupon certain initial data are taken, such as weight. Feet and shoes are also scanned at this point in time, as will be further explained.
With the person in place in the scanning zone, and disposed relatively stationary within that zone, the first scanning phase takes place to examine, sequentially, the laterally opposite sides of that person. When that scan is completed, and it is completed in a very short period of time, typically about 8-milliseconds, structure supporting the two panels rotates these panels through an arc of ninety-degrees, and stops the panels in the second scanning position relative to that subject, wherein the front and rear sides of the person are similarly scanned sequentially under a circumstance similar to that just described where the panels, and the subject between them, are again relatively fixed in positions with respect to one another. Subject height data, which is employed as one of the factors useful in selecting the appropriate dielectric-signature profile for evaluating scan data regarding each scanned person, is obtained from the results of this first scanning phase. Handily, this data is readily obtainable by noting which of the uppermost, combined, transmitter/receiver units that are employed during this phase do not create and receive “dielectric response”.
The second scanning operation completes the scan process for the single subject now being discussed, whereupon that subject turns a corner to the right or to the left (this is illustrated in the drawings) depending upon which is considered to be the exit side from the scanning zone, and exits through the now-rotated, open (see-through) space between the two panels. The panels are now positioned orthogonally with respect to the positions that they held when the first person just described was to be scanned, and the lead person in the orthogonally related other line of people now enters the scanning zone from the orthogonal location of that other line. Scanning of this next person takes place in much the same fashion just above described, except for the fact that, when the panel structure rotates through an arc of about ninety-degrees to perform the second scan of this “next” person, it effectively counter-rotates back to the position which it initially held in preparation for the previously explained scanning of the first person mentioned above. Scanning data is appropriately computer acquired from all scanning phases (two per person).
From the scanning data which is gathered with respect to each scanned person, that data is compared to a “map” or “schedule” of appropriate, physiologic, dielectric data relating to someone with a body type, height and weight similar to that of the person specifically being scanned, and any notable, dielectric-signature-related abnormalities cause an alarm state to go be created which causes security people, for example, to call the particular subject aside for further and more focused scanning inspection. No photographic imagery is developed from any scanning data. Rather, one of the output qualities of scanned data includes the presentation, on a simple wire-form human anatomy shape, of one or more highlighted general anatomic areas that show where a detected abnormality resides. This presentation of data is easily readable and assessable with little personnel-interpretive activity required. Output data may also be presented in a somewhat grid-like, or checkerboard-like, field of light and dark patches whose lightnesses and darknesses are interpretable to indicate the presence of a detected dielectric, non-physiologic abnormality.
Other features and unique advantages that are offered by the present invention will become more fully apparent as the description which now follows is read in conjunction with the accompanying drawings.